The earth rotates 90 degrees multiple times every day, so, uh, I'ma go with 'nothing'.

Oh wait, this is XKCD's What If, that dude has some funky ideas, I retract my statement and replace it with 'Some real bad shit probably.' :P

That's also a great demonstration of how map projections distort things.

Original static webpage version: https://what-if.xkcd.com/10/